Study of Turbulent Natural Convection in Vertical Storage Tubes for Supercritical Thermal Energy Storage

2014 ◽  
Vol 67 (2) ◽  
pp. 119-139 ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
Adrienne S. Lavine ◽  
H. Pirouz Kavehpour ◽  
Richard E. Wirz
Keyword(s):  
Natural Convection ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Turbulent Natural Convection

scholarly journals A Dimensionless Model for Transient Turbulent Natural Convection in Isochoric Vertical Thermal Energy Storage Tubes

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
Richard E. Wirz ◽  
Pirouz Kavehpour ◽  
Adrienne S. Lavine
Keyword(s):  
Natural Convection ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Convection Heat Transfer ◽  
Thermal Storage ◽  
Fourier Number ◽  
Turbulent Natural Convection ◽  
Wide Range ◽  
Rayleigh Numbers

In this study, turbulent natural convection heat transfer during the charge cycle of an isochoric vertically oriented thermal energy storage (TES) tube is studied computationally and analytically. The storage fluids considered in this study (supercritical CO2 and liquid toluene) cover a wide range of Rayleigh numbers. The volume of the storage tube is constant and the thermal storage happens in an isochoric process. A computational model was utilized to study turbulent natural convection during the charge cycle. The computational results were further utilized to develop a conceptual and dimensionless model that views the thermal storage process as a hot boundary layer that rises along the tube wall and falls in the center to replace the cold fluid in the core. The dimensionless model predicts that the dimensionless mean temperature of the storage fluid and average Nusselt number of natural convection are functions of L/D ratio, Rayleigh number, and Fourier number that are combined to form a buoyancy-Fourier number.

Transient Turbulent Natural Convection in Vertical Tubes for Indirect Thermal Energy Storage

2015 ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
H. Pirouz Kavehpour ◽  
Richard E. Wirz ◽  
Adrienne S. Lavine
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Convection Heat Transfer ◽  
Energy Storage System ◽  
Turbulent Natural Convection ◽  
Vertical Tubes

In this study, turbulent natural convection heat transfer during the charge cycle of a Thermal Energy Storage system was studied computationally and analytically. The storage fluids were supercritical CO2 and liquid toluene which are stored in vertical and sealed storage tubes. A computational model was developed and validated to study turbulent natural convection during the charge cycle. The results of this study show that the aspect ratio of the storage tube (L/D) has an important effect on the heat transfer characteristics. A conceptual model was developed that views the thermal storage process as a hot boundary layer that rises along the tube wall and falls in the center to replace the cold fluid in the core. This model shows that dimensionless mean temperature of the storage fluid and average Nusselt number are functions of a Buoyancy-Fourier number.

Transient Turbulent Natural Convection in Vertical Tubes for Thermal Energy Storage

2014 ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
H. Pirouz Kavehpour ◽  
Richard E. Wirz ◽  
Adrienne S. Lavine
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Convection Heat Transfer ◽  
Energy Storage System ◽  
Turbulent Natural Convection ◽  
Vertical Tubes

In this study, turbulent natural convection heat transfer during the charge cycle of a Thermal Energy Storage system was studied computationally and analytically. The storage fluids were supercritical CO2 and liquid toluene which are stored in vertical and sealed storage tubes. A computational model was developed and validated to study turbulent natural convection during the charge cycle. The results of this study show that the aspect ratio of the storage tube (L/D) has an important effect on the heat transfer characteristics. A conceptual model was developed that views the thermal storage process as a hot boundary layer that rises along the tube wall and falls in the center to replace the cold fluid in the core. This model shows that dimensionless mean temperature of the storage fluid and average Nusselt number are functions of a Buoyancy-Fourier number.

Effect of Natural Convection on Thermal Energy Storage in Supercritical Fluids

2013 ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
Adrienne S. Lavine ◽  
H. Pirouz Kavehpour ◽  
Gani B. Ganapathi ◽  
Richard E. Wirz
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Natural Convection ◽  
Energy Storage ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Thermal Storage

Heat transfer to the storage fluid is a critical subject in thermal energy storage systems. The storage fluids that are proposed for supercritical thermal storage system are organic fluids that have poor thermal conductivity; therefore, pure conduction will not be an efficient heat transfer mechanism for the system. The current study concerns a supercritical thermal energy storage system consisting of horizontal tubes filled with a supercritical fluid. The results of this study show that the heat transfer to the supercritical fluid is highly dominated by natural convection. The buoyancy-driven flow inside the storage tubes dominates the flow field and enhances the heat transfer dramatically. Depending on the diameter of the storage tube, the buoyancy-driven flow may be laminar or turbulent. The natural convection has a significant effect on reducing the charge time compared to pure conduction. It was concluded that although the thermal conductivity of the organic supercritical fluids are relatively low, the effective laminar or turbulent natural convection compensates for this deficiency and enables the supercritical thermal storage to charge effectively.

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